Various objects, including mineral resources such as iron ore and limestone, are conveyed by a conveyor belt. When being conveyed by the conveyor belt, the objects to be conveyed are fed onto an upper cover rubber of the conveyor belt from a hopper or another conveyor belt. The fed objects to be conveyed are loaded on the upper cover rubber and conveyed in a running direction of the conveyor belt. When the objects to be conveyed are fed onto the upper cover rubber of the conveyor belt, the upper cover rubber is subject to impact, and when the surfaces of the objects to be conveyed are sharp, the upper cover rubber sometimes sustains cut damage. When the objects to be conveyed are loaded on the upper cover rubber and conveyed, the upper cover rubber is subject to wear as a result of the objects to be conveyed sliding on the upper cover rubber. Thus, in the known art, various proposals have been made (see Japanese Unexamined Patent Application Publication No. 2001-88922A for example) in order to improve the wear resistance.
When sharp objects such as iron ore are conveyed, they slide while stuck into the upper cover rubber. This causes significant scratch abrasion. Scratch abrasion can easily reach the core layer of the conveyor belt, making it advantageous to accurately estimate the scratch abrasion resistance of the upper cover rubber.
Examples of testers for evaluating the wear resistance of rubber known in the art include the DIN (Deutsches Institut für Normung (German Institute for Standardization) abrasion tester and the Williams abrasion tester. These abrasion testers are not for obtaining the amount of scratch abrasion. Thus, there is a demand for a tester with a novel configuration for accurately estimating the scratch abrasion resistance of an upper cover rubber of a conveyor belt when actually used.